To control the temperature and humidity in its 50 acres of outdoor flower fields in Oxnard, Pyramid Flowers is pretty much at the mercy of Nature. But inside its 20 acres of greenhouses it’s a completely different story.

Here, a computer-controlled system of vents, hot-water pipes, shade cloth and heat curtains allows precise adjustments around the clock and throughout the year to provide exactly the indoor weather that will help the plants do best.

“We use and reuse heat,” says owner Fred Van Wingerden, whose family migrated here from the Netherlands in 1967. “You’re creating an artificial environment, so you want to do that as efficiently as possible.”

Inside this four-acre greenhouse, 100,000 brightly colored gerbera daisies are grown hydroponically in individual pots filled with cubes of rock wool. Sensors constantly monitor temperature, humidity and light, and feed the information to a mainframe computer that makes constant adjustments. Typically, 75° F. and 80% humidity are ideal.

Top: Inside this four-acre greenhouse, Fred Van Wingerden controls the weather.

Above Left: Vents in the roof automatically open and close in response to temperature and humidity.

Above Center: The heat curtain material is a very thin layer of plastic with a finely interwoven mesh of threads.

Above Right: Heat curtains creep open along suspension wires to keep heat down low, where it will do the most good.

To maximize its climate control while minimizing energy use, Pyramid uses several techniques:

Shade cloth. To cool things off on hot days, or to help protect on chilly nights, the computer can open vents in the roof and deploy an automated layer of shade cloth, which crawls along a network of wires near the ceiling.

Heat from hot water. To warm things up, the roof vents are closed and hot water from a gas-fired boiler is pumped through miles of steel pipes or plastic hoses running beneath the rows of plants.

Insulating heat curtains. Heat curtains, which run horizontally above the plants as well as down the walls, automatically creep open along their own network of wires. Their job, says Van Wingerden, is to keep the heat close to the plants, thereby reducing energy costs by about half. The Southern California Gas Co. helped to pay for their installation and periodic replacement through its Express Efficiency rebate program.

High-efficiency boiler and heat storage tank. The locomotive-sized 250-horsepower, 8,500-gallon high-efficiency boiler and pipes are heavily insulated, as is a massive heat storage tank outside, from which water often can be recirculated without reheating, minimizing run time for the boiler.

Electronic burner controls. Electronic burner controls using variable frequency drives help coax maximum BTUs from the natural gas fuel.

CO₂ condensers. Carbon dioxide from the boiler exhaust is captured using CO₂ condensers and pumped to each plant to promote healthy leaf growth.

A backup generator is always ready in case of a power outage. “When you have all these systems running, you don’t want to be out of power,” says Van Wingerden.